Thin, low power consuming panel displays have come to be used in large numbers as display devices for television receivers, computers, and portable terminals in recent years.
As such a panel display, there is known an active matrix type display device comprised of a large number of pixels using for example TFTs (thin film transistors) as switching elements arranged in a matrix on a glass substrate or other transparent insulating substrate (panel) in combination with liquid crystals or other substances having an electro-optic effect.
As such an active matrix type display device, Japanese Unexamined Patent Publication (Kokai) No. 4-242724 provides a liquid crystal display device forming part of the peripheral circuits formed on the substrate for driving the pixel unit by complementary TFTs similar to the active elements connected to the pixels and forming the remaining peripheral circuits by semiconductor chips.
FIG. 1A is a schematic view of the configuration of a liquid crystal display device as represented by the above Japanese Unexamined Patent Publication (Kokai) No. 4-242724, while FIG. 1B is a sectional view along the line A—A in FIG. 1A.
The liquid crystal display device shown in FIGS. 1A and 1B is a liquid crystal display device holding a liquid crystal layer 63 between a transparent insulating substrate 16 formed with for example a horizontal driver (HD) 14, vertical driver (VD) 13, and some other peripheral circuits formed by TFTs and a transparent insulating substrate arranged facing the same (counter substrate) 62, wherein the remaining peripheral circuits formed by semiconductor chips such as a timing controller (TC) 23, reference voltage generation circuit (REF) 24, and DC-DC converter (DDC) 25, that is, IC chips 23 to 25, are attached to the surface of the transparent insulating substrate 16 on the opposite side to the surface formed with the peripheral circuits 13 and 14 and are electrically connected with the peripheral circuits 13 and 14 by using a flexible cable 8.
Alternatively, as shown in FIG. 2, the remaining peripheral circuits formed by semiconductor chips such as the timing controller (TC) 23, reference voltage generation circuit (REF) 24, and DC-DC converter (DDC) 25, that is, the IC chips 23 to 25, are attached to the same surface of the transparent insulating substrate 16 formed with the horizontal driver (HD) 14, vertical driver (VD) 13, and some other peripheral circuits formed by TFTs and are electrically connected with the peripheral circuits 13 and 14.
In the liquid crystal display devices shown in FIGS. 1A and 1B, however, as shown in FIG. 1B, the thickness tb of the liquid crystal display device as a whole ends up becoming greater by at least the extent of the thickness ta of the IC chips 23 to 25 and the flexible cable 8, for example, by about 1 mm.
Therefore, the thickness of the device using the liquid crystal display device as a display unit also ends up becoming greater. In portable terminals, in particular mobile phones, effort is being made to reduce the thicknesses of the devices. If the thickness tb of the liquid crystal display device used as the display unit of a mobile phone is great, this would obstruct the reduction of thickness of the mobile phone itself.
Further, in the liquid crystal display device shown in FIG. 2, the total area of the peripheral circuits formed by the TFTs and the remaining IC chips 23 to 25 becomes the area of the periphery (frame), so there is the disadvantage that compactness is impaired. Further, there is the disadvantage that the ratio of the effective display area (liquid crystal display unit) in the liquid crystal display device ends up becoming smaller.